open_connection: Wrong server signature

[mkrueger]

I'm getting Wrong server signature.

I'm not doing something special - but I can't find the issue - any clues?

struct Client {}

#[async_trait]
impl client::Handler for Client {
    type Error = russh::Error;

    async fn check_server_key(
        &mut self,
        _server_public_key: &ssh_key::PublicKey,
    ) -> Result<bool, Self::Error> {
        Ok(true)
    }
}

...
        let config = client::Config {
            inactivity_timeout: Some(Duration::from_secs(5)),
            ..<_>::default()
        };

        let config = Arc::new(config);
        let sh = Client {};
        let mut session = russh::client::connect(config, addrs, sh).await?; // <- crash

Note: I'm writing a terminal app and need the library for the ssh connection part.

[Eugeny]

Which version of the crate are you using? Consider raising the log level to debug (the crate uses log, so you can use env_logger or similar) and checking the logs. Also which host key and kex algorithm is being used? (you'll see it in the log)

[mkrueger]

Thought I'm just doing an easy beginner error.

I'm using the git version - have tried the latests version 0.49.1 as well - same result.
Have problems connecting since ~1y or so.

It's an open source project so it's not urgent but I want to continue on that a bit.
(FYI https://github.com/mkrueger/icy_tools/blob/master/crates/icy_term/README.md)

Sure:

[2024-12-20T12:56:06Z DEBUG russh::ssh_read] read_ssh_id: reading
[2024-12-20T12:56:06Z DEBUG russh::ssh_read] read 18
[2024-12-20T12:56:06Z DEBUG russh::ssh_read] Ok("SSH-2.0-cryptlib\r\n")
[2024-12-20T12:56:06Z DEBUG russh::cipher] writing, seqn = 0
[2024-12-20T12:56:06Z DEBUG russh::cipher] padding length 7
[2024-12-20T12:56:06Z DEBUG russh::cipher] packet_length 972
[2024-12-20T12:56:06Z DEBUG russh::client] writing 976 bytes
[2024-12-20T12:56:06Z DEBUG russh::ssh_read] id 18 18
[2024-12-20T12:56:06Z DEBUG russh::cipher] reading, len = [0, 0, 1, 60]
[2024-12-20T12:56:06Z DEBUG russh::cipher] reading, seqn = 0
[2024-12-20T12:56:06Z DEBUG russh::cipher] reading, clear len = 316
[2024-12-20T12:56:06Z DEBUG russh::cipher] read_exact 320
[2024-12-20T12:56:06Z DEBUG russh::cipher] read_exact done
[2024-12-20T12:56:06Z DEBUG russh::cipher] reading, padding_length 42
[2024-12-20T12:56:06Z DEBUG russh::client::kex] extending []
[2024-12-20T12:56:06Z DEBUG russh::negotiation] kex 243
[2024-12-20T12:56:06Z DEBUG russh::negotiation] kex 280
[2024-12-20T12:56:06Z DEBUG russh::negotiation] kex 291
[2024-12-20T12:56:06Z DEBUG russh::negotiation] client_compression = None
[2024-12-20T12:56:06Z DEBUG russh::client::kex] algo = Names { kex: Name("diffie-hellman-group14-sha1"), key: Rsa { hash: Some(Sha256) }, cipher: Name("3des-cbc"), client_mac: Name("hmac-sha2-256"), server_mac: Name("hmac-sha2-256"), server_compression: None, client_compression: None, ignore_guessed: false, strict_kex: false }
[2024-12-20T12:56:06Z DEBUG russh::client::kex] write = []
[2024-12-20T12:56:06Z DEBUG russh::client::kex] i0 = 964
[2024-12-20T12:56:06Z DEBUG russh::cipher] writing, seqn = 1
[2024-12-20T12:56:06Z DEBUG russh::cipher] padding length 5
[2024-12-20T12:56:06Z DEBUG russh::cipher] packet_length 268
[2024-12-20T12:56:06Z DEBUG russh::client::kex] moving to kexdhdone, exchange = Exchange { client_id: CryptoVec { p: 0x7b618002bc00, size: 20, capacity: 32 }, server_id: CryptoVec { p: 0x7b618002bbe0, size: 16, capacity: 16 }, client_kex_init: CryptoVec { p: 0x7b6110003250, size: 964, capacity: 2048 }, server_kex_init: CryptoVec { p: 0x7b6110001090, size: 273, capacity: 512 }, client_ephemeral: CryptoVec { p: 0x7b6110003040, size: 257, capacity: 512 }, server_ephemeral: CryptoVec { p: 0x1, size: 0, capacity: 0 } }
[2024-12-20T12:56:07Z DEBUG russh::cipher] reading, len = [0, 0, 3, 124]
[2024-12-20T12:56:07Z DEBUG russh::cipher] reading, seqn = 1
[2024-12-20T12:56:07Z DEBUG russh::cipher] reading, clear len = 892
[2024-12-20T12:56:07Z DEBUG russh::cipher] read_exact 896
[2024-12-20T12:56:07Z DEBUG russh::cipher] read_exact done
[2024-12-20T12:56:07Z DEBUG russh::cipher] reading, padding_length 67
[2024-12-20T12:56:07Z DEBUG russh::client] server_public_Key: PublicKey { key_data: Rsa(RsaPublicKey { e: Mpint(010001), n: Mpint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}), comment: "" }
[2024-12-20T12:56:07Z DEBUG russh::client] kexdhdone.exchange = Exchange { client_id: CryptoVec { p: 0x7b618002bc00, size: 20, capacity: 32 }, server_id: CryptoVec { p: 0x7b618002bbe0, size: 16, capacity: 16 }, client_kex_init: CryptoVec { p: 0x7b6110003250, size: 964, capacity: 2048 }, server_kex_init: CryptoVec { p: 0x7b6110001090, size: 273, capacity: 512 }, client_ephemeral: CryptoVec { p: 0x7b6110003040, size: 257, capacity: 512 }, server_ephemeral: CryptoVec { p: 0x7b6110004740, size: 256, capacity: 256 } }
[2024-12-20T12:56:07Z DEBUG russh::client] exchange hash: CryptoVec { p: 0x7b6110002e20, size: 20, capacity: 32 }
[2024-12-20T12:56:07Z DEBUG russh::client] sig_type: "rsa-sha2-256"
[2024-12-20T12:56:07Z DEBUG russh::client] signature: b"\xa7\xd0+\xe23tX\tqz\xdd\0\xf1\x19.\xc4\xbd\x9b\xb8\xcfs\xf0\x87\x8a\x1f\xdd'g\xb9\xd4\xb0|\xdc\x03O\xe5\xa7\xdbZ\x01:TF\x9e\xcd\x9cy\xc2\xee}\xe4\xd65\x0f\xd2<\x19\0,\xf5\r\xc8|&Z\x08\x9ck\x91Y\x7f'\xd6N\x97?\x89E\xae\xba\xca\x9f5\x9cA\xf1\xa6\xbaAjVK\xf2T\xfb\xa1\x95Fe\xf3 \xd0\xd9m?\xb1\xaf9*\xa4\xc9O\xc6\x10\x91\xda5\xdd\xbc$\xa8zr\"\x84\xa2Y1\xf0\xaf\x8e\x12X\x95v\x1e\xb5\xfe\xf3Ca\xe1\xe1\x08sY\xd0\xd9\x9e\xbbOF\x0e/q{g\xf0\xb6n\x03\xbf\x02\xb9\x7f\xa78C\xa6c\x9c\x1b|\xeaKNhW\xd2\xfc\xaa\x18\xf7\xdf\xcaD\xe0o$JV#\x1eDX\x85\xfe\xc0\x96/\x942\xd0\x89\x1b\x8c\xabb\xe7\xf6LB\x9d\xdbg8\xf3``\x8f\xa4r\xb6\n\xc2\xf4\xdf\x84\xd3\xfc\x1czp\xb7Y\xbc\x08X\x9a\x03\x1fjF;\t\x88\xecH\x7fyL\n\x85.yN"
[2024-12-20T12:56:07Z DEBUG russh::client] wrong server sig
[2024-12-20T12:56:07Z DEBUG russh::client] drop session

Server is: 20forbeers.com:1338

It's a telnet BBS so it's up all the time.

I use an own preffered struct with all algorithms/ciphers for connecting :

        let mut preferred = Preferred::DEFAULT.clone();
        preferred.kex = Cow::Owned(kex::ALL_KEX_ALGORITHMS.iter().map(|k| **k).collect());
        preferred.cipher = Cow::Owned(cipher::ALL_CIPHERS.iter().map(|k| **k).collect());
        let config = client::Config {
            inactivity_timeout: Some(Duration::from_secs(5)),
            preferred,
            ..<_>::default()
        };

[Eugeny]

Can you confirm that it works with OpenSSH using this exact set of algorithms?

[2024-12-20T12:56:06Z DEBUG russh::client::kex] algo = Names { kex: Name("diffie-hellman-group14-sha1"), key: Rsa { hash: Some(Sha256) }, cipher: Name("3des-cbc"), client_mac: Name("hmac-sha2-256"), server_mac: Name("hmac-sha2-256"), server_compression: None, client_compression: None, ignore_guessed: false, strict_kex: false }

[mkrueger]

Works when using libssh-rs

Was porting over this code:
https://github.com/mkrueger/icy_term/blob/main/src/com/ssh.rs

Test case:

use std::time::Duration;

use libssh_rs::{Session, SshOption};

const SUPPORTED_CIPHERS: &str = "3des-cbc";
const SUPPORTED_KEY_EXCHANGES: &str = "diffie-hellman-group14-sha1";

fn main() {
    let session = Session::new().unwrap();

    session.set_option(SshOption::Hostname("20forbeers.com".to_string())).unwrap();
    session.set_option(SshOption::Port(1338)).unwrap();
    session.set_option(SshOption::KeyExchange(SUPPORTED_KEY_EXCHANGES.to_string())).unwrap();
    session.set_option(SshOption::CiphersCS(SUPPORTED_CIPHERS.to_string())).unwrap();
    session.set_option(SshOption::CiphersSC(SUPPORTED_CIPHERS.to_string())).unwrap();
    session.set_option(SshOption::Timeout(Duration::from_millis(5000))).unwrap();
    session.set_option(SshOption::LogLevel(libssh_rs::LogLevel::Warning)).unwrap();
    println!("Connecting to 20forbeers.com:1338...");
    session.connect().unwrap();
    println!("ok.");
}

Using:

[dependencies]
libssh-rs =  { version = "0.2.0", features = ["vendored", "vendored-openssl"] }

[mkrueger]

Thanks - helps but I've an other issue about that. Will open a bug.